Thanks, for the comment on my blog and for this image. I had misunderstood what you did. I would have done the same thing if I had received a hat with a brim like that!
If I ever get around to writing it, one of my next posts will talk about syle changes in Bowlers and Derbies over the decades, particularly between the 19th and 20th centuries. Mostly Derbies, as that's what I've studied the most, but I'll also talk about what are considered the differences between English and American styles.
Steam is good for most small things, though more severe creases sometimes require the denatured alcohol. I had one crease that was perpendicular to the edge of the brim and I was afraid the felt was actually split. The felt turned out to be okay, as the denatured alcohol softened and reset the shellac, solving the problem.
Thanks for the tip about denatured alcohol, if I come across a damaged hat that will be very useful information. As for the historical changes in style I would definitely be very much interested to read such an article. Clearly brim shape and crown height/shape have been changing enormously over time since the invention of the bowler and with the divergent American adoption of it as the derby. When will you end your historical review, the 1950s? That would seem reasonable to me because I question whether contemporary machine sewed brim bindings and their homburg shape can be considered a style, given that it's entirely a result of cheaper manufacturing rather than a conscious choice of styling. I also wonder why modern bowlers and derbies by old manufacturers all look so short and squat. An outgrowth of the article might be a comparison of historical top hats and bowler styles in the same eras, and how they converged and diverged, and whether there was a correlation or inverse correlation to stylistic changes in each type of hat.
Edit: this last because I consider the top hat and the bowler hat to be close cousins in many ways, the only really fundamental difference being crown shape.